84: yankng one's chain Mar 2, 2015

The idiom "yanking my chain" began with miners. Because washroom facilities are difficult to set up in 19th century mines, there would be a cart with a toilet seat on it that would move along the rails built for mine trolleys. As one would not want a bathroom to be moving while in use, miners would keep small chains to put in front of the wheels to keep them from turning. A common prank among miner-folk was to pull the chain out and allow the toilet carts to roll, with a person on it, through a mine.